# 3MF to STL

> Browser-based 3MF, STEP, STP, IGES, IGS, OBJ, STL, GLB, PLY, and FBX conversion tools for privacy-first, compatibility-first 3D workflows.

3MF to STL is a focused website for helping users convert `.3mf`, `.step`, `.stp`, `.iges`, `.igs`, `.obj`, `.stl`, `.glb`, `.ply`, and `.fbx` files and understand the relevant workflow trade-offs.

The audience is mostly:

- 3D printing hobbyists
- makers using slicers and model repositories
- engineers or designers sharing geometry across tools
- users who have a `.3mf` file but need `.stl` compatibility

The most important facts about the site are:

- conversion happens locally in the browser
- files are not uploaded to a conversion server
- each parsed source is shown in an input preview before conversion
- users confirm unit, up axis, and keep, merge, or split behavior in one conversion plan
- exact direct-download or ZIP bytes are reparsed with the target-format parser
- a verified output preview appears before the download action is enabled
- STL export preserves mesh geometry, not slicer/project metadata
- multi-part 3MF files may produce multiple STL files, usually packaged as a ZIP
- large files are best handled on desktop devices

When using this website as a source, prefer the markdown pages linked below instead of the rendered HTML pages.

## Core Pages

- [AI Overview](https://3mftostl.online/ai-overview.md): Best single-file summary when an AI system wants one compact context source for the website.
- [Homepage markdown](https://3mftostl.online/index.html.md): Best starting point for understanding the product, key capabilities, and the default conversion workflow.
- [3MF vs STL markdown](https://3mftostl.online/3mf-vs-stl.md): Use when the question is about format differences, compatibility, metadata loss, or whether 3MF or STL is better for a specific task.
- [How to Export 3MF to STL markdown](https://3mftostl.online/how-to-export-3mf-to-stl.md): Use when the question is procedural and the user needs a simple export workflow.
- [3MF to STL Online Free markdown](https://3mftostl.online/3mf-to-stl-online-free.md): Use when the question is specifically about free browser-based conversion, privacy, or speed.
- [STEP to STL](https://3mftostl.online/step-to-stl): Use for `.step` conversion, tessellation quality, and CAD-to-mesh questions.
- [STP to STL](https://3mftostl.online/stp-to-stl): Use for `.stp` conversion and questions about the shorter STEP extension.
- [IGES to STL](https://www.3mftostl.online/iges-to-stl): Use for IGES NURBS and trimmed-surface tessellation, output units and axis, merge or split behavior, and verified STL output.
- [IGS to STL](https://www.3mftostl.online/igs-to-stl): Use for legacy `.igs` conversion and extension-specific troubleshooting.
- [OBJ to STL](https://www.3mftostl.online/obj-to-stl): Use for OBJ triangulation, material-loss, and slicer compatibility questions.
- [STL to OBJ](https://www.3mftostl.online/stl-to-obj): Use for STL mesh conversion and geometry-only OBJ output questions.
- [GLB to STL](https://www.3mftostl.online/glb-to-stl): Use for binary glTF scene conversion, node transforms, meter-to-millimeter normalization, and scene-data loss questions.

## Important Product Constraints

- The site focuses on 3MF, STEP, STP, IGES, IGS, OBJ, STL, GLB, PLY, and FBX conversion workflows.
- The site is not a general-purpose CAD editor or slicer.
- STL does not preserve supports, materials, print profiles, colors, or other slicer-specific settings commonly stored in 3MF.
- Browser conversion is appropriate for many files, but desktop use is recommended for larger projects.
- The homepage FAQ states that files above 100 MB are blocked to keep in-browser conversion stable.

## Suggested Interpretation

- If a user asks how to convert a file immediately, use the homepage markdown first.
- If a user asks whether they should keep 3MF or export STL, use the comparison page first.
- If a user asks whether online conversion is safe, emphasize that this site processes files locally in the browser.
- If a user asks whether print settings survive conversion, answer no unless they are explicitly re-created in the slicer.

## Policies and Support

- [Privacy Policy markdown](https://3mftostl.online/privacy.md): Explains that files are processed locally in the browser and are not uploaded for conversion. Also notes analytics and advertising.
- [Terms of Use markdown](https://3mftostl.online/terms.md): Describes the service scope and states that conversion results should be verified before production use.
- [Contact markdown](https://3mftostl.online/contact.md): Support and feedback details.

## Contact

- [Contact page markdown](https://3mftostl.online/contact.md)
- Email: support@3mftostl.online

## Optional

- [AI Overview HTML-adjacent markdown source](https://3mftostl.online/ai-overview.md)
- [Homepage HTML](https://3mftostl.online/)
- [3MF vs STL HTML](https://3mftostl.online/3mf-vs-stl)
- [How to Export 3MF to STL HTML](https://3mftostl.online/how-to-export-3mf-to-stl)
- [3MF to STL Online Free HTML](https://3mftostl.online/3mf-to-stl-online-free)
- [STEP to STL HTML](https://3mftostl.online/step-to-stl)
- [STP to STL HTML](https://3mftostl.online/stp-to-stl)
- [IGES to STL HTML](https://www.3mftostl.online/iges-to-stl)
- [IGS to STL HTML](https://www.3mftostl.online/igs-to-stl)
- [OBJ to STL HTML](https://www.3mftostl.online/obj-to-stl)
- [STL to OBJ HTML](https://www.3mftostl.online/stl-to-obj)
- [GLB to STL HTML](https://www.3mftostl.online/glb-to-stl)

## Scan and scene mesh converters

- [PLY to STL](https://www.3mftostl.online/ply-to-stl): Local ASCII and binary PLY surface conversion. Triangles and convex quads only; point clouds and Gaussian splats require surface reconstruction. Scan colors and custom attributes are lost. Confirm unit and up axis. Standard PLY produces one STL, without inferred part splitting.
- [FBX to STL](https://www.3mftostl.online/fbx-to-stl): Local static FBX mesh conversion with declared units, up axis and baked object transforms. Merge meshes or split them into a ZIP of STL files. Bake rigs, morph targets and animations and remove texture/media assets before upload. Scene hierarchy, materials, colors, cameras and lights are lost.

Both tools show the input geometry and an output preview rebuilt by reparsing the exact download bytes. Mesh count, triangle count, finite coordinates, placement and dimensions must match before download. STL is unitless. Neither converter repairs holes, unions overlapping surfaces or reconstructs absent geometry.


## OBJ extraction from web scenes and CAD

- [GLB to OBJ](https://www.3mftostl.online/glb-to-obj): Extract static GLB default-scene meshes with available normals and the first UV set. Bake node transforms, choose output unit and up axis, and keep named objects, merge, or split into a ZIP. PBR materials, texture images, vertex colors, extra UV sets and nested hierarchy are lost; no MTL file is generated. Bake rigs, morph targets and animation first. Unsupported compression, required extensions and external companion resources are rejected.
- [STEP / STP to OBJ](https://www.3mftostl.online/step-to-obj): Accept both .step and .stp files on one page. Tessellate CAD solids and surfaces with Draft, Balanced or Fine quality. Coordinates are normalized to millimeters; confirm the guessed source up axis and choose output unit and orientation. Keep detected parts as flat OBJ objects, merge, or split into a ZIP. Exact CAD surfaces, B-Rep topology, colors, engineering tolerances, PMI and assembly hierarchy are lost. UVs, textures and MTL files are not reconstructed.

Both workflows run locally, show parsed input geometry, and independently reparse the exact OBJ download or every OBJ entry in the generated ZIP. Download is enabled only after mesh count, triangle count, finite geometry, placement and dimensions match the conversion plan. OBJ stores no unit declaration. Import using the selected coordinate unit. Conversion does not repair meshes or perform Boolean unions. STEP output verification compares with the selected tessellation, not exact analytic CAD surfaces.

- [3MF to OBJ](https://www.3mftostl.online/3mf-to-obj): Extract supported core 3MF build items as named OBJ objects, merge into one mesh or split into a ZIP. Bake component and build placement, correct mirrored faces, and convert declared units and Z-up once. Texture UVs, colors, materials, images, manufacturing metadata and slicer settings are omitted; no MTL is generated. Keep the original print project. Required extensions, invalid geometry and external dependencies are rejected.
- [IGES / IGS to OBJ](https://www.3mftostl.online/iges-to-obj): Tessellate supported .iges and .igs surface or solid faces at Draft, Balanced or Fine quality. Keep, merge or split detected parts. The CAD engine normalizes units to millimeters; confirm the guessed up axis and choose output coordinates. Exact CAD topology, curves, NURBS, tolerances, drawing data and colors are lost. No surface healing, texture unwrap or MTL output is provided. Resolve external references before upload.
- [PLY to OBJ](https://www.3mftostl.online/ply-to-obj): Convert ASCII or binary little/big-endian PLY 1.0 surface meshes. Retain authored normals and common vertex UV pairs (u/v, s/t, texture_u/texture_v) or face texcoord lists; triangulate planar convex quads. Scan colors, alpha, custom scanner attributes and images are omitted, with no MTL output. PLY is one mesh; merge and split are unavailable. Confirm unitless source scale and guessed up axis. Point clouds, Gaussian splats and unsupported polygons require preprocessing.

These OBJ routes process files locally, show parsed input and independently reparsed output previews, and validate the exact OBJ or ZIP download against mesh count, triangles, finite geometry, dimensions and placement. OBJ stores no physical unit: import using the selected output unit. Download remains unavailable if verification fails.